[PATCH] drm/self_refresh: Fix possible NULL deref in failure path

[Sean Paul]

From: Sean Paul <seanpaul at chromium.org>

If state allocation fails, we still try to give back the reference on
it. Also initialize ret in case the crtc is not enabled and we hit the
eject button.

Fixes: 1452c25b0e60 ("drm: Add helpers to kick off self refresh mode in drivers")
Cc: Daniel Vetter <daniel at ffwll.ch>
Cc: Jose Souza <jose.souza at intel.com>
Cc: Zain Wang <wzz at rock-chips.com>
Cc: Tomasz Figa <tfiga at chromium.org>
Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>
Cc: Sam Ravnborg <sam at ravnborg.org>
Cc: Sean Paul <seanpaul at chromium.org>
Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
Cc: Maxime Ripard <maxime.ripard at bootlin.com>
Cc: Sean Paul <sean at poorly.run>
Cc: David Airlie <airlied at linux.ie>
Cc: dri-devel at lists.freedesktop.org
Reported-by: Dan Carpenter <dan.carpenter at oracle.com>
Signed-off-by: Sean Paul <seanpaul at chromium.org>
---
 drivers/gpu/drm/drm_self_refresh_helper.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_self_refresh_helper.c b/drivers/gpu/drm/drm_self_refresh_helper.c
index e0d2ad1f070cb..4b9424a8f1f1c 100644
--- a/drivers/gpu/drm/drm_self_refresh_helper.c
+++ b/drivers/gpu/drm/drm_self_refresh_helper.c
@@ -69,14 +69,14 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work)
 	struct drm_connector *conn;
 	struct drm_connector_state *conn_state;
 	struct drm_crtc_state *crtc_state;
-	int i, ret;
+	int i, ret = 0;
 
 	drm_modeset_acquire_init(&ctx, 0);
 
 	state = drm_atomic_state_alloc(dev);
 	if (!state) {
 		ret = -ENOMEM;
-		goto out;
+		goto out_drop_locks;
 	}
 
 retry:
@@ -116,6 +116,8 @@ static void drm_self_refresh_helper_entry_work(struct work_struct *work)
 	}
 
 	drm_atomic_state_put(state);
+
+out_drop_locks:
 	drm_modeset_drop_locks(&ctx);
 	drm_modeset_acquire_fini(&ctx);
 }
-- 
Sean Paul, Software Engineer, Google / Chromium OS